Little shaver BLADE [not sure I see a blade as little though I get the pun]

AMOI crossed with AVION --- at least they’re the same language and “par avion” appears on envelopes, maybe a hundred thousandth.SENHOR [first Portuguese I’ve seen in a puzzle]ALLE [this might be fair considering “uber alles” is known in our history]

Too bad the theme is hidden --- a word like STOP in the grid would highlight it.